From related art, for example, as shown in Patent Document 1 below, a vibration-proofing device which includes a first mounting member connected to one of a vibration generation unit and a vibration reception unit, a second mounting member connected to the other, an actuator which dampens and absorbs the input vibration by reciprocally moving a movable element in accordance with the input vibration, an actuator case which houses the actuator therein, and a terminal mounted on the actuator case to electrically connect a connector of the actuator and an external power supply, and in which the actuator case is formed by insert molding using the terminal as an insert product is known.